P
US9028985B2ActiveUtilityPatentIndex 48

Recording media with multiple exchange coupled magnetic layers

Assignee: DESAI MRUGESHPriority: Mar 31, 2011Filed: Mar 31, 2011Granted: May 12, 2015
Est. expiryMar 31, 2031(~4.7 yrs left)· nominal 20-yr term from priority
Inventors:DESAI MRUGESHKANG KYONGHAZHOU JIANACHARYA B RAMAMURTHY
G11B 5/66G11B 5/65G11B 5/672G11B 5/678
48
PatentIndex Score
1
Cited by
375
References
26
Claims

Abstract

A magnetic recording (PMR) disk structure is described. The PMR disk structure may include a magnetic capping layer being substantially free of an oxide, an upper magnetic layer with an oxide content disposed directly below and in contact with the magnetic capping layer, and an upper exchange coupling layer disposed below the upper magnetic layer.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. A perpendicular magnetic recording disk, comprising:
 a magnetic capping layer being substantially free of an oxide; 
 an upper magnetic layer comprising a first oxide material, the upper magnetic layer disposed directly below and in contact with the magnetic capping layer, the upper magnetic layer having a first anisotropy field (H k ); 
 an upper exchange coupling layer disposed below and in contact with the upper magnetic layer; 
 an intermediate magnetic layer disposed below the upper exchange coupling layer, the intermediate magnetic layer having a second H k ; 
 a lower exchange coupling layer disposed below the intermediate magnetic layer; and 
 a lower magnetic layer disposed between the lower exchange coupling layer and a substrate, the lower magnetic layer having a third H k , wherein the third H k  is greater than the second H k , and wherein the second H k  is greater than the first H k . 
 
     
     
       2. The perpendicular magnetic recording disk of  claim 1 , wherein the first oxide material has a molar volume in a range of 5% to 30% of the upper magnetic layer. 
     
     
       3. The perpendicular magnetic recording disk of  claim 1 , wherein the upper magnetic layer has a thickness in a range of 0.5 nanometers (nm) to 5 nm. 
     
     
       4. The perpendicular magnetic recording disk of  claim 1 , wherein the first oxide material in the upper magnetic layer comprises titanium dioxide (TiO 2 ) or cobalt oxide (CoO). 
     
     
       5. The perpendicular magnetic recording disk of  claim 1 , wherein the magnetic capping layer has a fourth H k  being less than or equal to the first H k . 
     
     
       6. The perpendicular magnetic recording disk of  claim 5 , wherein the first H k  is in a range of 10 kilo-Oersted (kOe) to 20 kOe. 
     
     
       7. The perpendicular magnetic recording disk of  claim 1 , wherein the magnetic capping layer has a first inter-granular lateral exchange coupling and the upper magnetic layer has a second inter-granular lateral exchange coupling being less than the first inter-granular lateral exchange coupling. 
     
     
       8. The perpendicular magnetic recording disk of  claim 1 , wherein the intermediate magnetic layer comprises a first intermediate magnetic sub-layer having a fourth anisotropy field (H k ) and a second intermediate magnetic sub-layer above the first intermediate magnetic sub-layer having the second H k , the second H k  being less than the fourth H k , and the second intermediate magnetic sub-layer being substantially free of an oxide. 
     
     
       9. The perpendicular magnetic recording disk of  claim 8 , wherein the fourth H k  is in a range of 7 kilo-Oersted (kOe) to 20 kOe. 
     
     
       10. The perpendicular magnetic recording disk of  claim 9 , wherein the third H k  is greater than or equal to the fourth H k . 
     
     
       11. The perpendicular magnetic recording disk of  claim 8 , wherein the first intermediate magnetic sub-layer comprises a second oxide material. 
     
     
       12. The perpendicular magnetic recording disk of  claim 11 , wherein the second oxide material has a molar volume in a range of 5% to 30% of the first intermediate magnetic sub-layer. 
     
     
       13. The perpendicular magnetic recording disk of  claim 11 , wherein the second oxide material in the first intermediate magnetic sub-layer comprises titanium dioxide (TiO 2 ) or cobalt oxide (CoO). 
     
     
       14. The perpendicular magnetic recording disk of  claim 11 , wherein the first intermediate magnetic sub-layer has a first inter-granular lateral exchange coupling and the second intermediate magnetic sub-layer has a second inter-granular lateral exchange coupling being greater than the first inter-granular lateral exchange coupling. 
     
     
       15. The perpendicular magnetic recording disk of  claim 1 , wherein the lower magnetic layer comprises a first lower magnetic sub-layer having the third H k  and a second lower magnetic sub-layer above the first lower magnetic sub-layer having a fourth H k  being less than or equal to the third H k . 
     
     
       16. The perpendicular magnetic recording disk of  claim 15 , wherein the third H k  is in a range of 13 kilo-Oersted (kOe) to 25 kOe. 
     
     
       17. The perpendicular magnetic recording disk of  claim 15 , wherein the first lower magnetic sub-layer comprises a second oxide material. 
     
     
       18. The perpendicular magnetic recording disk of  claim 17 , wherein the second oxide material has a molar volume in a range of 5% to 30% of the first lower magnetic sub-layer. 
     
     
       19. The perpendicular magnetic recording disk of  claim 17 , wherein the second lower magnetic sub-layer comprises a third oxide material. 
     
     
       20. The perpendicular magnetic recording disk of  claim 19 , wherein the third oxide material has a molar volume in a range of 5% to 30% of the second lower magnetic sub-layer. 
     
     
       21. The perpendicular magnetic recording disk of  claim 15 , wherein the second lower magnetic sub-layer comprises a second oxide material. 
     
     
       22. The perpendicular magnetic recording disk of  claim 21 , wherein the second oxide material has a molar volume in a range of 5% to 30% of the second lower magnetic sub-layer. 
     
     
       23. A perpendicular magnetic recording disk, comprising:
 a magnetic capping layer being substantially free of an oxide; 
 an upper magnetic layer comprising a first oxide material, the upper magnetic layer disposed directly below and in contact with the magnetic capping layer; 
 an upper exchange coupling layer disposed below the upper magnetic layer 
 an intermediate magnetic layer disposed below the upper exchange coupling layer; 
 a lower exchange coupling layer disposed below the intermediate magnetic layer; and 
 a lower magnetic layer disposed between the lower exchange coupling layer and a substrate, wherein the lower magnetic layer comprises a first lower magnetic sub-layer having a first anisotropy field (H k ) and a second lower magnetic sub-layer above the first lower magnetic sub-layer having a second H k  being less than or equal to the first H k , and wherein the intermediate magnetic layer has a third H k  being less than or equal to the second H k , and the magnetic capping layer has a fourth H k  being less than the third H k . 
 
     
     
       24. A perpendicular magnetic recording disk, comprising:
 a magnetic capping layer being substantially free of an oxide; 
 an upper magnetic layer comprising an oxide material, the upper magnetic layer disposed directly below and in contact with the magnetic capping layer; 
 an upper exchange coupling layer disposed below the upper magnetic layer; 
 an intermediate magnetic layer disposed below the upper exchange coupling layer, the intermediate magnetic layer comprising a first intermediate magnetic sub-layer having a first anisotropy field (H k ) and a second intermediate magnetic sub-layer disposed above the first intermediate magnetic sub-layer having a second H k  being less than or equal to the first H k ; 
 a lower exchange coupling layer disposed below the intermediate magnetic layer; 
 a lower magnetic layer disposed between the lower exchange coupling layer and a substrate, the lower magnetic layer comprising a first lower magnetic sub-layer having a third H k  and a second lower magnetic sub-layer above the first lower magnetic sub-layer having a fourth H k  being less than or equal to the third H k , wherein the first H k  is less than the fourth H k ; and 
 a soft magnetic underlayer (SUL) of the perpendicular magnetic recording disk disposed between the substrate and the lower magnetic layer. 
 
     
     
       25. The perpendicular magnetic recording disk of  claim 24 , wherein the oxide material has a molar volume in a range of 5% to 30% of the upper magnetic layer. 
     
     
       26. The perpendicular magnetic recording disk of  claim 24 , wherein the oxide material in the upper magnetic layer comprises titanium dioxide (TiO 2 ) or cobalt oxide (CoO).

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